In order to transmit or record a moving image efficiently, a moving image coding device generating coded data by coding the moving image and a moving image decoding device generating a decoded image by decoding the coded data are used.
As a specific moving image coding scheme, for example, schemes (see NPL 1) proposed in H.264/MPEG-4.AVC and High-Efficiency Video Coding (HEVC) which is its successor codec can be exemplified.
In such a moving image coding scheme, an image (picture) forming a moving image is managed with a hierarchical structure configured to include a slice obtained by splitting an image, a coding unit (also referred to as a coding unit) obtained by splitting the slice, and a block and a partition obtained by splitting the coding unit, and is normally coded/decoded for each block.
In such a moving image coding scheme, generally, a predicted image is generated based on a local decoded image obtained by coding/decoding an input image and a prediction residual (also referred to as a “difference image” or a “residual image”) obtained by subtracting the predicted image from the input image (original image) is coded. As a method of generating a predicted image, inter-screen prediction (inter-prediction) and in-screen prediction (intra prediction) can be exemplified.
In the intra-prediction, predicted images in the same frame are sequentially generated based on local decoded images in the same frame.
In the inter-prediction, predicted images are generated by applying motion compensation prediction on reference pictures included in a reference picture list. The reference pictures are a subset of local decoded images in regard to a coded/decoded frame recorded in a picture buffer. Reference picture specifying information indicating which local decoded image in the picture buffer is a reference picture is included in header information. Reference picture order information indicating an order in which reference pictures are arranged in a reference picture list is also included in the header information.